The passage of rotatable shafts across pressure boundaries is common in the power generation, heating, ventilating and air conditioning, and other process and energy industries. Such rotatable shafts must be both supported, typically with journal bearings or the like, and sealed, usually at the point of passage across a pressure barrier such as a duct wall or other gas tight membrane.
One typical situation occurs wherein a damper is disposed in a stream of flowing gas for the regulation thereof. The damper may be manipulated by means of a rotatable shaft passing out of the duct to engage an externally mounted actuator. As the gas pressure within the duct may be 2 or more psi greater than ambient. Although it is well known in the prior art to provide separate journal bearings and seals for the rotatable shaft in such applications, a bearing combining the sealing and support functions would greatly simplify and reduce the costs of construction and maintenance.